In a Multimedia Priority Service (MPS) of Long Term Evolution (LTE), it has been considered that a mobile device is notified of priority call information indicating a priority level of processing for an terminating call included in an terminating call signal (PAGING) or an RRC control signal such as an RRC CONNECTION RELEASE (see Non-Patent Document 1). The mobile device executes priority control of the terminating call based on the informed priority level.
Meanwhile, CS (Circuit Switched) fallback (hereinafter, CSFB) from an LTE system (hereinafter, LTE) to a 3G system (hereinafter, 3G) is specified such that a mobile device follows access class barring information (AC/DSAC/PPAC) set in 3G when transmitting an RRC CONNECTION REQUEST in 3G (see Non-Patent Document 2).